kern_cons.c revision 331722 
1/*-
2 * Copyright (c) 1988 University of Utah.
3 * Copyright (c) 1991 The Regents of the University of California.
4 * Copyright (c) 1999 Michael Smith
5 * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
6 *
7 * All rights reserved.
8 *
9 * This code is derived from software contributed to Berkeley by
10 * the Systems Programming Group of the University of Utah Computer
11 * Science Department.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 *    notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 *    notice, this list of conditions and the following disclaimer in the
20 *    documentation and/or other materials provided with the distribution.
21 * 4. Neither the name of the University nor the names of its contributors
22 *    may be used to endorse or promote products derived from this software
23 *    without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 *	from: @(#)cons.c	7.2 (Berkeley) 5/9/91
38 */
39
40#include <sys/cdefs.h>
41__FBSDID("$FreeBSD: stable/11/sys/kern/kern_cons.c 331722 2018-03-29 02:50:57Z eadler $");
42
43#include "opt_ddb.h"
44#include "opt_syscons.h"
45
46#include <sys/param.h>
47#include <sys/systm.h>
48#include <sys/lock.h>
49#include <sys/mutex.h>
50#include <sys/conf.h>
51#include <sys/cons.h>
52#include <sys/fcntl.h>
53#include <sys/kdb.h>
54#include <sys/kernel.h>
55#include <sys/malloc.h>
56#include <sys/msgbuf.h>
57#include <sys/namei.h>
58#include <sys/priv.h>
59#include <sys/proc.h>
60#include <sys/queue.h>
61#include <sys/reboot.h>
62#include <sys/sysctl.h>
63#include <sys/sbuf.h>
64#include <sys/tty.h>
65#include <sys/uio.h>
66#include <sys/vnode.h>
67
68#include <ddb/ddb.h>
69
70#include <machine/cpu.h>
71#include <machine/clock.h>
72
73static MALLOC_DEFINE(M_TTYCONS, "tty console", "tty console handling");
74
75struct cn_device {
76	STAILQ_ENTRY(cn_device) cnd_next;
77	struct		consdev *cnd_cn;
78};
79
80#define CNDEVPATHMAX	32
81#define CNDEVTAB_SIZE	4
82static struct cn_device cn_devtab[CNDEVTAB_SIZE];
83static STAILQ_HEAD(, cn_device) cn_devlist =
84    STAILQ_HEAD_INITIALIZER(cn_devlist);
85
86int	cons_avail_mask = 0;	/* Bit mask. Each registered low level console
87				 * which is currently unavailable for inpit
88				 * (i.e., if it is in graphics mode) will have
89				 * this bit cleared.
90				 */
91static int cn_mute;
92static char *consbuf;			/* buffer used by `consmsgbuf' */
93static struct callout conscallout;	/* callout for outputting to constty */
94struct msgbuf consmsgbuf;		/* message buffer for console tty */
95static u_char console_pausing;		/* pause after each line during probe */
96static char *console_pausestr=
97"<pause; press any key to proceed to next line or '.' to end pause mode>";
98struct tty *constty;			/* pointer to console "window" tty */
99static struct mtx cnputs_mtx;		/* Mutex for cnputs(). */
100static int use_cnputs_mtx = 0;		/* != 0 if cnputs_mtx locking reqd. */
101
102static void constty_timeout(void *arg);
103
104static struct consdev cons_consdev;
105DATA_SET(cons_set, cons_consdev);
106SET_DECLARE(cons_set, struct consdev);
107
108void
109cninit(void)
110{
111	struct consdev *best_cn, *cn, **list;
112
113	/*
114	 * Check if we should mute the console (for security reasons perhaps)
115	 * It can be changes dynamically using sysctl kern.consmute
116	 * once we are up and going.
117	 *
118	 */
119        cn_mute = ((boothowto & (RB_MUTE
120			|RB_SINGLE
121			|RB_VERBOSE
122			|RB_ASKNAME)) == RB_MUTE);
123
124	/*
125	 * Find the first console with the highest priority.
126	 */
127	best_cn = NULL;
128	SET_FOREACH(list, cons_set) {
129		cn = *list;
130		cnremove(cn);
131		/* Skip cons_consdev. */
132		if (cn->cn_ops == NULL)
133			continue;
134		cn->cn_ops->cn_probe(cn);
135		if (cn->cn_pri == CN_DEAD)
136			continue;
137		if (best_cn == NULL || cn->cn_pri > best_cn->cn_pri)
138			best_cn = cn;
139		if (boothowto & RB_MULTIPLE) {
140			/*
141			 * Initialize console, and attach to it.
142			 */
143			cn->cn_ops->cn_init(cn);
144			cnadd(cn);
145		}
146	}
147	if (best_cn == NULL)
148		return;
149	if ((boothowto & RB_MULTIPLE) == 0) {
150		best_cn->cn_ops->cn_init(best_cn);
151		cnadd(best_cn);
152	}
153	if (boothowto & RB_PAUSE)
154		console_pausing = 1;
155	/*
156	 * Make the best console the preferred console.
157	 */
158	cnselect(best_cn);
159
160#ifdef EARLY_PRINTF
161	/*
162	 * Release early console.
163	 */
164	early_putc = NULL;
165#endif
166}
167
168void
169cninit_finish()
170{
171	console_pausing = 0;
172}
173
174/* add a new physical console to back the virtual console */
175int
176cnadd(struct consdev *cn)
177{
178	struct cn_device *cnd;
179	int i;
180
181	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
182		if (cnd->cnd_cn == cn)
183			return (0);
184	for (i = 0; i < CNDEVTAB_SIZE; i++) {
185		cnd = &cn_devtab[i];
186		if (cnd->cnd_cn == NULL)
187			break;
188	}
189	if (cnd->cnd_cn != NULL)
190		return (ENOMEM);
191	cnd->cnd_cn = cn;
192	if (cn->cn_name[0] == '\0') {
193		/* XXX: it is unclear if/where this print might output */
194		printf("WARNING: console at %p has no name\n", cn);
195	}
196	STAILQ_INSERT_TAIL(&cn_devlist, cnd, cnd_next);
197	if (STAILQ_FIRST(&cn_devlist) == cnd)
198		ttyconsdev_select(cnd->cnd_cn->cn_name);
199
200	/* Add device to the active mask. */
201	cnavailable(cn, (cn->cn_flags & CN_FLAG_NOAVAIL) == 0);
202
203	return (0);
204}
205
206void
207cnremove(struct consdev *cn)
208{
209	struct cn_device *cnd;
210	int i;
211
212	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
213		if (cnd->cnd_cn != cn)
214			continue;
215		if (STAILQ_FIRST(&cn_devlist) == cnd)
216			ttyconsdev_select(NULL);
217		STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
218		cnd->cnd_cn = NULL;
219
220		/* Remove this device from available mask. */
221		for (i = 0; i < CNDEVTAB_SIZE; i++)
222			if (cnd == &cn_devtab[i]) {
223				cons_avail_mask &= ~(1 << i);
224				break;
225			}
226#if 0
227		/*
228		 * XXX
229		 * syscons gets really confused if console resources are
230		 * freed after the system has initialized.
231		 */
232		if (cn->cn_term != NULL)
233			cn->cn_ops->cn_term(cn);
234#endif
235		return;
236	}
237}
238
239void
240cnselect(struct consdev *cn)
241{
242	struct cn_device *cnd;
243
244	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
245		if (cnd->cnd_cn != cn)
246			continue;
247		if (cnd == STAILQ_FIRST(&cn_devlist))
248			return;
249		STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
250		STAILQ_INSERT_HEAD(&cn_devlist, cnd, cnd_next);
251		ttyconsdev_select(cnd->cnd_cn->cn_name);
252		return;
253	}
254}
255
256void
257cnavailable(struct consdev *cn, int available)
258{
259	int i;
260
261	for (i = 0; i < CNDEVTAB_SIZE; i++) {
262		if (cn_devtab[i].cnd_cn == cn)
263			break;
264	}
265	if (available) {
266		if (i < CNDEVTAB_SIZE)
267			cons_avail_mask |= (1 << i);
268		cn->cn_flags &= ~CN_FLAG_NOAVAIL;
269	} else {
270		if (i < CNDEVTAB_SIZE)
271			cons_avail_mask &= ~(1 << i);
272		cn->cn_flags |= CN_FLAG_NOAVAIL;
273	}
274}
275
276int
277cnunavailable(void)
278{
279
280	return (cons_avail_mask == 0);
281}
282
283/*
284 * sysctl_kern_console() provides output parseable in conscontrol(1).
285 */
286static int
287sysctl_kern_console(SYSCTL_HANDLER_ARGS)
288{
289	struct cn_device *cnd;
290	struct consdev *cp, **list;
291	char *p;
292	int delete, error;
293	struct sbuf *sb;
294
295	sb = sbuf_new(NULL, NULL, CNDEVPATHMAX * 2, SBUF_AUTOEXTEND |
296	    SBUF_INCLUDENUL);
297	if (sb == NULL)
298		return (ENOMEM);
299	sbuf_clear(sb);
300	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
301		sbuf_printf(sb, "%s,", cnd->cnd_cn->cn_name);
302	sbuf_printf(sb, "/");
303	SET_FOREACH(list, cons_set) {
304		cp = *list;
305		if (cp->cn_name[0] != '\0')
306			sbuf_printf(sb, "%s,", cp->cn_name);
307	}
308	sbuf_finish(sb);
309	error = sysctl_handle_string(oidp, sbuf_data(sb), sbuf_len(sb), req);
310	if (error == 0 && req->newptr != NULL) {
311		p = sbuf_data(sb);
312		error = ENXIO;
313		delete = 0;
314		if (*p == '-') {
315			delete = 1;
316			p++;
317		}
318		SET_FOREACH(list, cons_set) {
319			cp = *list;
320			if (strcmp(p, cp->cn_name) != 0)
321				continue;
322			if (delete) {
323				cnremove(cp);
324				error = 0;
325			} else {
326				error = cnadd(cp);
327				if (error == 0)
328					cnselect(cp);
329			}
330			break;
331		}
332	}
333	sbuf_delete(sb);
334	return (error);
335}
336
337SYSCTL_PROC(_kern, OID_AUTO, console, CTLTYPE_STRING|CTLFLAG_RW,
338	0, 0, sysctl_kern_console, "A", "Console device control");
339
340/*
341 * User has changed the state of the console muting.
342 * This may require us to open or close the device in question.
343 */
344static int
345sysctl_kern_consmute(SYSCTL_HANDLER_ARGS)
346{
347	int error;
348
349	error = sysctl_handle_int(oidp, &cn_mute, 0, req);
350	if (error != 0 || req->newptr == NULL)
351		return (error);
352	return (error);
353}
354
355SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
356	0, sizeof(cn_mute), sysctl_kern_consmute, "I",
357	"State of the console muting");
358
359void
360cngrab()
361{
362	struct cn_device *cnd;
363	struct consdev *cn;
364
365	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
366		cn = cnd->cnd_cn;
367		if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG))
368			cn->cn_ops->cn_grab(cn);
369	}
370}
371
372void
373cnungrab()
374{
375	struct cn_device *cnd;
376	struct consdev *cn;
377
378	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
379		cn = cnd->cnd_cn;
380		if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG))
381			cn->cn_ops->cn_ungrab(cn);
382	}
383}
384
385/*
386 * Low level console routines.
387 */
388int
389cngetc(void)
390{
391	int c;
392
393	if (cn_mute)
394		return (-1);
395	while ((c = cncheckc()) == -1)
396		cpu_spinwait();
397	if (c == '\r')
398		c = '\n';		/* console input is always ICRNL */
399	return (c);
400}
401
402int
403cncheckc(void)
404{
405	struct cn_device *cnd;
406	struct consdev *cn;
407	int c;
408
409	if (cn_mute)
410		return (-1);
411	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
412		cn = cnd->cnd_cn;
413		if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
414			c = cn->cn_ops->cn_getc(cn);
415			if (c != -1)
416				return (c);
417		}
418	}
419	return (-1);
420}
421
422void
423cngets(char *cp, size_t size, int visible)
424{
425	char *lp, *end;
426	int c;
427
428	cngrab();
429
430	lp = cp;
431	end = cp + size - 1;
432	for (;;) {
433		c = cngetc() & 0177;
434		switch (c) {
435		case '\n':
436		case '\r':
437			cnputc(c);
438			*lp = '\0';
439			cnungrab();
440			return;
441		case '\b':
442		case '\177':
443			if (lp > cp) {
444				if (visible)
445					cnputs("\b \b");
446				lp--;
447			}
448			continue;
449		case '\0':
450			continue;
451		default:
452			if (lp < end) {
453				switch (visible) {
454				case GETS_NOECHO:
455					break;
456				case GETS_ECHOPASS:
457					cnputc('*');
458					break;
459				default:
460					cnputc(c);
461					break;
462				}
463				*lp++ = c;
464			}
465		}
466	}
467}
468
469void
470cnputc(int c)
471{
472	struct cn_device *cnd;
473	struct consdev *cn;
474	char *cp;
475
476#ifdef EARLY_PRINTF
477	if (early_putc != NULL) {
478		if (c == '\n')
479			early_putc('\r');
480		early_putc(c);
481		return;
482	}
483#endif
484
485	if (cn_mute || c == '\0')
486		return;
487	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
488		cn = cnd->cnd_cn;
489		if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
490			if (c == '\n')
491				cn->cn_ops->cn_putc(cn, '\r');
492			cn->cn_ops->cn_putc(cn, c);
493		}
494	}
495	if (console_pausing && c == '\n' && !kdb_active) {
496		for (cp = console_pausestr; *cp != '\0'; cp++)
497			cnputc(*cp);
498		cngrab();
499		if (cngetc() == '.')
500			console_pausing = 0;
501		cnungrab();
502		cnputc('\r');
503		for (cp = console_pausestr; *cp != '\0'; cp++)
504			cnputc(' ');
505		cnputc('\r');
506	}
507}
508
509void
510cnputs(char *p)
511{
512	int c;
513	int unlock_reqd = 0;
514
515	if (use_cnputs_mtx) {
516	  	/*
517		 * NOTE: Debug prints and/or witness printouts in
518		 * console driver clients can cause the "cnputs_mtx"
519		 * mutex to recurse. Simply return if that happens.
520		 */
521		if (mtx_owned(&cnputs_mtx))
522			return;
523		mtx_lock_spin(&cnputs_mtx);
524		unlock_reqd = 1;
525	}
526
527	while ((c = *p++) != '\0')
528		cnputc(c);
529
530	if (unlock_reqd)
531		mtx_unlock_spin(&cnputs_mtx);
532}
533
534static int consmsgbuf_size = 8192;
535SYSCTL_INT(_kern, OID_AUTO, consmsgbuf_size, CTLFLAG_RW, &consmsgbuf_size, 0,
536    "Console tty buffer size");
537
538/*
539 * Redirect console output to a tty.
540 */
541void
542constty_set(struct tty *tp)
543{
544	int size;
545
546	KASSERT(tp != NULL, ("constty_set: NULL tp"));
547	if (consbuf == NULL) {
548		size = consmsgbuf_size;
549		consbuf = malloc(size, M_TTYCONS, M_WAITOK);
550		msgbuf_init(&consmsgbuf, consbuf, size);
551		callout_init(&conscallout, 0);
552	}
553	constty = tp;
554	constty_timeout(NULL);
555}
556
557/*
558 * Disable console redirection to a tty.
559 */
560void
561constty_clear(void)
562{
563	int c;
564
565	constty = NULL;
566	if (consbuf == NULL)
567		return;
568	callout_stop(&conscallout);
569	while ((c = msgbuf_getchar(&consmsgbuf)) != -1)
570		cnputc(c);
571	free(consbuf, M_TTYCONS);
572	consbuf = NULL;
573}
574
575/* Times per second to check for pending console tty messages. */
576static int constty_wakeups_per_second = 5;
577SYSCTL_INT(_kern, OID_AUTO, constty_wakeups_per_second, CTLFLAG_RW,
578    &constty_wakeups_per_second, 0,
579    "Times per second to check for pending console tty messages");
580
581static void
582constty_timeout(void *arg)
583{
584	int c;
585
586	if (constty != NULL) {
587		tty_lock(constty);
588		while ((c = msgbuf_getchar(&consmsgbuf)) != -1) {
589			if (tty_putchar(constty, c) < 0) {
590				tty_unlock(constty);
591				constty = NULL;
592				break;
593			}
594		}
595
596		if (constty != NULL)
597			tty_unlock(constty);
598	}
599	if (constty != NULL) {
600		callout_reset(&conscallout, hz / constty_wakeups_per_second,
601		    constty_timeout, NULL);
602	} else {
603		/* Deallocate the constty buffer memory. */
604		constty_clear();
605	}
606}
607
608static void
609cn_drvinit(void *unused)
610{
611
612	mtx_init(&cnputs_mtx, "cnputs_mtx", NULL, MTX_SPIN | MTX_NOWITNESS);
613	use_cnputs_mtx = 1;
614}
615
616SYSINIT(cndev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, cn_drvinit, NULL);
617
618/*
619 * Sysbeep(), if we have hardware for it
620 */
621
622#ifdef HAS_TIMER_SPKR
623
624static int beeping;
625static struct callout beeping_timer;
626
627static void
628sysbeepstop(void *chan)
629{
630
631	timer_spkr_release();
632	beeping = 0;
633}
634
635int
636sysbeep(int pitch, int period)
637{
638
639	if (timer_spkr_acquire()) {
640		if (!beeping) {
641			/* Something else owns it. */
642			return (EBUSY);
643		}
644	}
645	timer_spkr_setfreq(pitch);
646	if (!beeping) {
647		beeping = period;
648		callout_reset(&beeping_timer, period, sysbeepstop, NULL);
649	}
650	return (0);
651}
652
653static void
654sysbeep_init(void *unused)
655{
656
657	callout_init(&beeping_timer, 1);
658}
659SYSINIT(sysbeep, SI_SUB_SOFTINTR, SI_ORDER_ANY, sysbeep_init, NULL);
660#else
661
662/*
663 * No hardware, no sound
664 */
665
666int
667sysbeep(int pitch __unused, int period __unused)
668{
669
670	return (ENODEV);
671}
672
673#endif
674
675/*
676 * Temporary support for sc(4) to vt(4) transition.
677 */
678static unsigned vty_prefer;
679static char vty_name[16];
680SYSCTL_STRING(_kern, OID_AUTO, vty, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, vty_name,
681    0, "Console vty driver");
682
683int
684vty_enabled(unsigned vty)
685{
686	static unsigned vty_selected = 0;
687
688	if (vty_selected == 0) {
689		TUNABLE_STR_FETCH("kern.vty", vty_name, sizeof(vty_name));
690		do {
691#if defined(DEV_SC)
692			if (strcmp(vty_name, "sc") == 0) {
693				vty_selected = VTY_SC;
694				break;
695			}
696#endif
697#if defined(DEV_VT)
698			if (strcmp(vty_name, "vt") == 0) {
699				vty_selected = VTY_VT;
700				break;
701			}
702#endif
703			if (vty_prefer != 0) {
704				vty_selected = vty_prefer;
705				break;
706			}
707#if defined(DEV_VT)
708			vty_selected = VTY_VT;
709#elif defined(DEV_SC)
710			vty_selected = VTY_SC;
711#endif
712		} while (0);
713
714		if (vty_selected == VTY_VT)
715			strcpy(vty_name, "vt");
716		else if (vty_selected == VTY_SC)
717			strcpy(vty_name, "sc");
718	}
719	return ((vty_selected & vty) != 0);
720}
721
722void
723vty_set_preferred(unsigned vty)
724{
725
726	vty_prefer = vty;
727#if !defined(DEV_SC)
728	vty_prefer &= ~VTY_SC;
729#endif
730#if !defined(DEV_VT)
731	vty_prefer &= ~VTY_VT;
732#endif
733}
734
735